POS0701 LONG-TERM EFFICACY OF TOCILIZUMAB MONOTHERAPY AFTER ULTRA-SHORT GLUCOCORTICOID ADMINISTRATION TO TREAT GIANT CELL ARTERITIS – TWO YEAR FOLLOW-UP OF THE GUSTO TRIAL
Authors: L. Christ, L. Seitz, G. Scholz, L. Bütikofer, F. Kollert, B. Maurer, S. Reichenbach, P. Villiger
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Two randomised controlled trials (RCT) [1, 2] demonstrated a glucocorticoid (GC)-sparing effect of tocilizumab (TCZ) of at least 50% in the treatment of giant cell arteritis (GCA). The GUSTO (GCA treatment with Ultra-Short glucocorticoids and TOcilizumab) trial was set up to evaluate the efficacy and safety of TCZ-monotherapy after a 3-day GC-pulse in new-onset GCA. <h3>Objectives</h3> The objectives of this analysis were to explore the maintenance of remission 2 years after discontinuation of TCZ treatment (drug-free remission) and the effectiveness or retreatment with TCZ after relapse. Data up to week 156 are presented. <h3>Methods</h3> Eighteen patients with newly diagnosed GCA were enrolled in this investigator-initiated, single-arm, single-center, open-label clinical trial [3]. Patients received 500 mg methylprednisolone intravenously for 3 consecutive days. Thereafter, GC treatment was discontinued and TCZ (8 mg/kg bodyweight) was administered intravenously, followed by weekly subcutaneous TCZ injections (162 mg) from day 10 until week 52. Patients in clinical remission stopped TCZ at week 52 and entered the follow-up study. Maintenance of efficacy at week 156 included the proportion of patients with complete relapse-free remission of disease at week 156, and time to first relapse after week 52. <h3>Results</h3> At baseline there were 12/18 female patients, and the median age was 72 (range 67-75) years. Overall, 15/18 complained of cranial symptoms (10/18 jaw claudication, 6/18 visual symptoms), 10/18 suffered from polymyalgia rheumatica symptoms, 16/18 had positive ultrasound findings of the cranial arteries, and in 13/18 temporal arterial biopsies showed a characteristic histopathology. At week 52, 13/18 patients were in relapse-free remission and entered the follow-up study. One out of 13 patients presented with a minor relapse at week 72. Remission was achieved after restart of TCZ-monotherapy. At week 156, 12/18 patients were in relapse-free remission. <h3>Conclusion</h3> After a 3-days pulse of methylprednisolone followed by 52 weeks of TCZ monotherapy, drug-free remission was maintained until week 156 in all but one patient entering long-term extension (12/13, 92%). This relapse rate is substantially lower than reported in the RCTs [1,2]. It may – at least in part – be explained by the patient characteristics (exclusively new diagnoses), and presumably by the intensive initial treatment consisting of a 3-day GC pulse, immediately followed by TCZ. As a proof-of-concept study, the protocol is not intended to be used in everyday clinical practice. <h3>References</h3> [1]Villiger, et al. Lancet, 2016 [2]Stone, et al. NEJM, 2017 [3]Christ, et al. Lancet Rheumatol, 2021 <h3>Acknowledgements</h3> We thank Sabine Hasler, Andrea Ziörjen Kipfer, Barbara Strehler, and Astrid Zbinden for their outstanding support in conducting of the study. <h3>Disclosure of Interests</h3> Lisa Christ Shareholder of: Gilead Sciences and F. Hoffmann-La Roche Ltd, Consultant of: Bristol-Myers Squibb and Novartis, Grant/research support from: Gilead Sciences, F. Hoffmann-La Roche Ltd, and Pfizer, Luca Seitz: None declared, Godehard Scholz: None declared, Lukas Bütikofer: None declared, Florian Kollert Shareholder of: Roche, Consultant of: BMS, Actelion, Boehringer-Ingelheim, Pfizer, Grant/research support from: Roche, Gilead, Pfizer, Employee of: Roche and was previously employed by Novartis, Britta Maurer Speakers bureau: Boehringer-Ingelheim, GSK, Novartis as well as congress support from Medtalk, Pfizer, Roche, Actelion, Mepha, and MSD, Consultant of: Novartis, Boehringer Ingelheim, Janssen-Cilag, GSK, Grant/research support from: AbbVie, Protagen, Novartis Biomedical, Stephan Reichenbach: None declared, Peter Villiger Speakers bureau: Roche, MSD, Abbvie, Pfizer, Novartis, Grünenthal, Celgene, Sanofi, Chugai, Consultant of: MSD, Abbvie, Pfizer, Novartis, Celgene, Sanofi, Bristol-Meyers-Squibb (BMS), Grant/research support from: Roche, MSD, Abbvie.